We have been developing a method for long-term culture of retinal_explants taken from rat embryos. The tissue has been used to test for toxic effects of prospective adhesives involved in the repair of torn retinas. The system is also being developed as a transducer in co-culture with colliculus for basic studies in neurophysiology and pharmacology. The tissue can be maintained in a normal state for at least 4 days, enough for the toxicity study. We have tested Matrigel, cyanoacrylate, Celltak, and blood components for toxicity and as a substrate for growth and healing. None of the test materials provided an optimum combination of tensile strength and growth substrate properties.